Papers by Keyword: Phenol

Abstract: Increasing the fire resistance of wooden building structures is quite effectively ensured thanks to the development of fire-fighting compositions with aromatic components that contribute to the formation of a carbonized layer on the surface of the material during combustion. It is also known about the mutual positive influence of benzene fragments and phosphate-containing compounds on the fire-resistant characteristics of wood. The paper considers the possibility of complex use of phenol and orthophosphate acid to improve the flame retardant properties of SiO₂-based coatings. The effect of modifying additives on the rheological properties of silicic acid sols was determined. Based on the results of IR spectroscopy, the influence of components on the nature of polycondensation in experimental SiO₂ sols was evaluated. It is shown that the use of orthophosphate acid as a modifier leads to the initiation of predominantly linear polycondensation in experimental sols. It was established that small additions of phenol practically do not affect the course of polycondensation in experimental sols. Increasing the phenol content to 0.5% showed an effect on gel formation due to the possible addition of phenol to the skeletal silanol groups by the donor-acceptor mechanism, which makes it possible to have a synergistic effect of the complex additive of orthophosphate acid and phenol on the properties of the silica-containing flame retardant composition.

Abstract: TiO₂ is the most widely used photocatalytic material to degrade waste compounds. To improve the photocatalytic performance of TiO₂, graphene nanoplatelets were used as doping on TiO₂. Graphene nanoplatelets are a hybrid between graphene and graphite. Graphene nanoplatelets have attractive features, including mechanical toughness, and for composite material applications. In this report, we investigate the effect of calcination on the synthesis of graphene nanoplatelets-TiO₂ synthesis material for photocatalytic processes. Graphene nanoplatelets-TiO₂ composites were prepared by stirring and evaporation methods. Then the composite was calcined at a temperature of 400°C, 500°C 600°C at intervals for 1, 2, 3 hours respectively. The composites were confirmed by X-ray diffraction (XRD), FTIR, SEM, BET, and UV-vis. The effect of calcination temperature on the surface, morphology, microstructure and photocatalytic activity of the graphene nanoplatelets-TiO₂ composite was investigated further. The photocatalytic performance of the graphene nanoplatelets-TiO₂ composite was evaluated for the photodegradation of phenol in an aqueous solution under a mercury lamp. Based on the results of the performance test in degrading phenol, the best results were obtained at a calcination temperature of 500°C for 3 hours. From the results of the characterization, it can be explained that 500°C calcination of this composite can improve the photocatalytic process in degrading of phenol.

Abstract: Water is a valuable source that directly impact human life. The expansions of globalization as well industrialization led to water pollution, thus became worsen over the time. The issue of degradation of organic and inorganic pollutants become very serious from ecological point of view, especially organic pollutants in industrial effluents due to difficult to be remove by means of conventional technologies. Phenol compound in wastewater effluents can threatens the human and public health, water supplies, and has negative impacts on the ecosystems. In addition, the TiO₂ semiconductor metal oxide provides a great interest among researchers to overcome this problem via photocatalytic reaction under advanced oxidation processes (AOPs). The AOPs mainly used the hydroxyl radicals to attack and destroy a wide range of harmful dyes into non-toxic products, CO₂ and water at ambient temperature. Therefore, in this study, the synthesized TiO₂ catalyst gave the remarkable degradation of phenol up to 96.3%, meanwhile the commercial TiO₂ only show 80.3%, in respectively under similar optimum conditions of 10 mg/L at pH 5 with dosage of 1.25 g/L within 90 mins time reaction under light irradiation.

Abstract: This article presents the results of studies considering the possibility of obtaining products based on phenol-formaldehyde oligomers of reduced toxicity, material consumption and corrosive activity. This is achieved by removing free phenol and formaldehyde monomers from the foaming composition and by more complete implementation of hydrodynamic processes during foaming of the composition. The article includes the results of studies on finding the ratio of the initial components and its effect on the corrosive activity of finished products. It is also considered the determination of the dependences of the toxicity and material consumption of phenolic foams on the pressure gradient of the foaming composition and the environment. For the research, the FRV-1A resole prepolymer and the VAG-3 foaming-hardening agent were used as raw materials. The content of phenol and formaldehyde monomers was determined by gas chromatography. In this work, the diagram of installation is developed and presented. It consists of a high-pressure machine, a mold, a vacuum pump, a vacuum gauge, air supply and air removal pipes. The results indicate that ensuring the formation of a cellular structure of phenolic foam in the low-pressure zone makes it possible to obtain heat-insulating products based on phenol-formaldehyde oligomers of reduced toxicity, material consumption and corrosive activity.

Abstract: Biofilm enhances the performances of biological wastewater treatment systems. This study aimed to investigate the feasibility of using biodegradable polyhydroxyalkanoate (PHA) pellets as novel biofilm carrier for phenol biodegradation. Two identical laboratory-scale reactors were operated with fill, react, settle, draw and idle periods in the ratio of 2:12:2:1:7 for a 24-h cycle. One reactor was supplemented with 2% (v/v) of PHA pellet and operated as sequencing batch biofilm reactor (SBBR), whereas the other reactor was operated as sequencing batch reactor (SBR) and used as the control reactor. The performances of SBBR and SBR in degrading phenol were studied at three phases with the introduction of 300, 500 and 1000 mg L^-1 phenol, respectively. The removal of phenol was found best described using zero-order kinetics, with R² > 0.97. At all phases, the phenol removal rate during react period for SBBR (7.30 ± 0.55 to 9.33 ± 1.06 mg L^-1 min^-1) was found higher compared to those for SBR (4.28 ± 0.66 to 8.35 ± 0.68 mg L^-1 min^-1), with significance difference observed at low phenol concentration. Whereas for chemical oxygen demand biodegradation kinetics, SBRR exhibited significantly higher rate compared to SBR at all phases. From the scanning electron microscopy image, the attachment of activated sludge onto PHA pellet was observed. The results indicated the potential of PHA serving as alternative biofilm carrier in biofilm process.

Abstract: The present study deals with the investigation of catalytic cycloalkylation reactions of phenol with 1-methylcyclopentene. KU-23 and aluminum phenolate were used as catalysts for the process. The effect of kinetic parameters (temperature, duration, molar ratios of the initial components and the amount of catalyst) on the yield and selectivity of methylcyclopentyl phenols obtained as a result of scientific research was investigated. As a result, effective conditions were found for the production of para- and ortho-, ortho- (1-methylcyclopentyl) phenols with high yield and selectivity. It was determined that high yield of target product in the presence of phenol, 1-methylcyclopentene and catalyst KU-23, was 71.2% for phenol and selectivity for target product - 92.8% is obtained under the following conditions of cycloalkylation reaction: temperature 110°C, reaction time-5 hours, molar ratio phenol to methylcyclopentene-1 : 1, the amount of catalyst-10% according to the phenol taken. The cycloalkylation reaction of phenol with 1-methylcyclopentene in the presence of aluminum phenolate catalyst was carried out in an autoclave in a nitrogen environment and effective conditions were found: temperature 260°C, reaction time - 5 hours, molar ratio of phenol to 1-methylcyclopentene 1: 2, amount of catalyst 20% according to the phenol taken. Under these conditions, the yield of the target product is 44.3% for the phenol taken, and the selectivity is 87.6% for the target product. The chemical structures of the synthesized para- and ortho-, ortho- (1-methylcyclopentyl) phenols were confirmed by IR-, ¹H and NMR spectroscopy, and physicochemical parameters were determined.

Abstract: The research on phenolic compound degradation using chemical oxidation methods in a plasma reactor was performed with an Ozone-Plasma Hybrid Reactor (RHOP). This device operates by combining ozonation reactions in the liquid plasma within the reaction room. Furthermore, Ozone gas as a reagent is produced by the standard ozonator type Resun RSO-9805 made in Hong Kong and fed into this device, where the liquid phase is mixed within the injector. This way, the two-phase mixture reacts more intensively in RHOP. Also, this combination is designed to intensify hydroxyl radicals while the liquid phase is in an alkaline condition constantly exposed to plasma. The results demonstrated a continuous circulation for 2 hours at the initial concentration of 50 ppm for p-chlorophenol with a volume of 2 liters. This further obtained an 83.98% removal rate and 42.19% COD value decrease.

Abstract: The paper presents the results of studies of the reaction of the interaction of phenol with cyclohexene (CH) in the presence of a Zeolite-Y catalyst impregnated with phosphoric acid and studying the dependence on the yield and selectivity of the target product on various parameters. As a result of the study of the phenol cycloalkylation by cyclohexene, optimal conditions were found, the yield of which is 81.6 % of theory for the taken CH, and the selectivity is 94.0 % for the target product. The developed mathematical model of the processes of the interaction of phenol with cyclohexene in the form of a regression polynomial made it possible to find the optimal values ​​of the input variables.

Abstract: Water pollution is one of the most common problem in industrialized society owing to increase in manufacturing process. Phenol is one of the water pollutant subsequently released into the waste water in manufacturing papers, paints, textile and plastics. Phenol caused serious health effect if in contact with human hence removal of this substance from waste water is crucial. Using bio sorbent in adsorption of phenol offered a green and cheap method for phenol removal particularly in Bandung area where supply of bio sorbent from agricultural waste are abundant. Biomass from Chinese cabbage (Brassica Pekinensis L.) contains cellulose, hemicellulose and lignin, among other substances that present in smaller amount. Dried stems were blended and filtered through 140 mesh and washed with ethanol to provide biosorbent. Modification was carried out by treatment with epichlorohydrin and HCl. Biosorbents were characterized using FTIR, SEM and BET analysis. Adsorption study was carried out according to the following parameters: pH range 5-9, contact time 10-80 minutes, mass of biosorbent 0.2-1.1 g and initial concentration of phenol is 10-50 mg/L. Upon adsorption, the concentration of phenol was measured by HPLC analysis at the following parameter: eluent methanol: water 7:3 v/v, flowrate 0.8 mL/minute at 273 nm. Untreated biosorbent showed adsorption capacity 0.097 mg/g whilst treatment with epichlorohydrine and HCl showed a decrease in adsorption capacity of 0.057 mg/g and 0.059 mg/g respectively. The optimum adsorption capacity was obtained at pH 8, 20 minutes contact time, 0.8 g mass of biosorbent and initial phenol concentration of 10 mg/L.

Abstract: A phenol imprinted polymer modified electrode has been prepared by electropolymerization technique in the solution containing aniline as monomer and phenol as a template onto carbon paste electrode surface. A potentiometric method was used to evaluate the performance of the electrodes. Optimization of aniline and phenol composition and a number of polymerization cycles was investigated based on the Nernstian factor. The performance of the electrode sensor is affected by the pH of the analyte solution. Based on the potential response of three different electrodes, it is known that MIP modified electrode has better sensitivity than non-imprinted electrode or bare carbon paste electrode.